Existing mobile radio networks, such as the network which operates in accordance with the GSM standard, offer only limited possibilities for transmitting non-spoken messages such as text data. For example, short messages having a maximum of 160 characters can be transmitted as texts. This arrangement is designated SMS (Short Message Service). The data sender has to pay for the cost of sending such text messages.
A charging method is disclosed in EP 0 753 957 A2 in which a GSM user as sender sends an SMS message to an Internet user as recipient. In the text field (i.e., in the user data) of the transmitted SMS message, the GSM user can also insert a reply stamp at his/her cost. If the recipient inserts this stamp in an SMS reply to the original sender in the reply text, this reply remains free of cost to him/her.
WO 00/41415 merely relates to a coordination procedure for obtaining replies from mobile radio device users in response to an inquiry via SMS messages. In this case, the respective answering mobile radio device user is, if appropriate, not charged for his/her SMS reply.
A corresponding coordination procedure is also provided by WO 98/09451 on the basis of SMS, in which a credit is made to the account of the person queried for returning a reply; e.g., to a survey to the sender of the latter.
A transmission of multimedia data, in particular still or moving images with or without sound, also will be possible in the future. A considerable increase in the data transmission volumes within such transmissions is expected, as is a considerable increase in the number of messages to be transmitted, together resulting in an increase in costs.
A transmission service for multimedia data is, for example, the so-called Multimedia Messaging Service (MMS) in the UMTS (Universal Mobile Telecommunication Service) radio communication system. Details of this can be found in the specification ETSI TS 123 140 V3.0.1 Universal Mobile Telecommunications System (UMTS); Multimedia Messaging Service (MMS), Functional description; stage 2 (e G TS 23.140 version 3.0.1 Release 1999).
The present invention addresses the problem of simplifying the control and manipulation of costs for subscribers to a mobile radio network.